1. Field of the Invention
This invention relates to a process for conducting a reaction taking place at elevated temperature in which heat-sensitive products are formed.
2. Description of the Related Art
The invention relates in particular to discontinuous processes, such as esterification, transesterification, glycerinolysis, aminolysis and Guerbet reactions. The reaction mixture, which, in the case of esterification reactions for example, may consist of fatty acids, alcohols, catalysts and, optionally, other reactants, is introduced into a stirred tank reactor and heated to the reaction temperature which is normally in the range from about 200.degree. to 250.degree. C. The reactor is heated by pipe coils arranged externally on and/or in the tank through which a heating medium, for example heating steam, flows. The heating phase is followed by reaction times of from about 3 to 20 hours. The products are then cooled and purified.
Since the heat exchange surface to be installed in or on the reactor is limited by the predetermined geometry and dimensions of the stirred reactor, the volume-time yield also has an upper limit. The reaction also cannot be carried out at a higher temperature to increase throughput because the products formed and, generally, the products used are sensitive to heat. This sensitivity to heat leads to partial decomposition, to cracking processes and other secondary sections. Secondary reactions involving the desired reaction products also occur to a significant extent.
In addition, the increase in boiling point in that part of the reaction mixture which is situated at the bottom of the stirred tank reactor prevents the rapid dissipation of overheating which also results in unwanted secondary reactions.